JP2011141440A - Toner for electrostatic charge image development - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a toner for electrostatic charge image development, which is excellent in charging property and property of fog prevention and prevents contamination of members even in the case of a high-speed long-life machine. <P>SOLUTION: The toner for electrostatic charge image development is a negative charging toner which is toner base particles containing at least a binder resin and a colorant and has at least melamine resin fine particles deposited or fixed on the surface, wherein when the ratio Dv/Dn of the volume median diameter Dv to the number median diameter Dn is denoted as (A), and the standard deviation of the circular-equivalent diameter (volume basis) of the melamine resin particles is denoted as (B), (A) and (B) satisfy a relational expression (1):B≤-41.7A+53.2. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an electrostatic charge image developing toner used in electrophotography, electrostatic photography and the like.

  In recent years, copiers and printers using electrophotographic technology have become widespread, and even faster and higher image quality has been achieved by expanding to full color and graphic applications, etc., and downsizing of devices and improving maintainability by expanding the user base. Market demand from many viewpoints, such as environmental response, is increasing. At that time, the functions required of consumption members such as toners are becoming increasingly sophisticated. For example, improvement in chargeability of toners is becoming more important because it leads to higher image quality.

If the charge of the toner is low or the charge start-up is bad, the poorly charged toner adheres to the background portion which should be white, which causes image defects called fogging. In addition, the chargeability is sensitively affected by temperature and humidity. In particular, in a high-temperature and high-humidity environment, the toner is reduced in charge, resulting in further fogging.
In order to prevent this, various studies for improving the charging property have been made. As one of them, a technique for attaching positively chargeable particles to the surface of a negatively chargeable toner is known. This is used as a so-called microcarrier that improves the negative chargeability of the toner by the presence of a small amount of positively charged particles in the system when the toner is triboelectrically charged. Materials have been studied.

  An example of such a material is melamine resin particles. It is known that melamine-based resin particles exhibit a strong positive chargeability and thus effectively function as the above-described microcarriers, and can adhere to the surface of a negatively chargeable toner to improve the chargeability of the toner. For example, Patent Documents 1 to 4 disclose that a melamine resin particle or a composite containing the main component is externally added to a negatively chargeable toner.

JP 2001-13718 JP 2003-57869 A Japanese Unexamined Patent Publication No. 2005-140952 JP 2005-202131 A

  However, melamine-based resin particles have the demerit of easily contaminating members in the developing tank as well as the merit of improving the chargeability of the toner. In recent years, there has been an increasing demand for electrophotography with higher image quality, higher machine speed, and longer developer life, all of which are in the direction of promoting member contamination. In the toners described in (4) to (4), even if a certain degree of effect is observed in reducing fog due to the improvement in chargeability, image defects due to contamination of members may occur in some cases and the performance is not always satisfactory.

Compared with the two-component development method, the non-magnetic one-component development method is advantageous for downsizing and maintenance of the apparatus because of its relatively simple structure, while the stress on the toner from the toner layer regulating member is severe, If toner using melamine resin particles is used for this, contamination of the toner layer regulating member with melamine resin particles and vertical streak-like image defects occur, making it more difficult to use than the two-component method. Become. In addition, in the non-magnetic one-component development method, the charge rising of the toner is particularly important. For this reason, when a large amount of melamine resin particles are added, there is a trade-off that the above-mentioned member contamination is further deteriorated.

  In view of the circumstances as described above, there has been a demand for a technique that uses melamine-based resin particles capable of imparting a favorable negative chargeability to the toner and at the same time satisfies the problem of member contamination.

  The present invention has been made in view of the background art, and its problems are to provide a toner for developing an electrostatic image having excellent chargeability, good fog, and high-speed, long-life machine free from member contamination. There is to do.

The present inventor has repeatedly studied to solve the above problems, and has found that the above problems can be solved by controlling the physical properties of the melamine resin particles within a specific range. The present invention is based on this finding, and the gist of the present invention is as follows.
1. A negatively chargeable toner comprising at least a binder resin and a colorant and having at least melamine resin particles adhered or fixed to a surface thereof, wherein the ratio of the volume median diameter Dv to the number median diameter Dn is Dv / An electrostatic charge image developing toner, wherein Dn is A and the standard deviation of the equivalent circle diameter (volume basis) of the melamine resin particles is B, which satisfies the following relational expression (1).
B ≦ −41.7A + 53.2 (1)
2. 2. The electrostatic image developing toner according to 1 above, wherein A and B satisfy the following relational expression (2).
B ≦ −41.7A + 52.4 (2)
3. 3. The electrostatic charge image developing toner according to 1 or 2, wherein the melamine resin particles have an equivalent circle diameter (volume basis) of 9 μm or less.
4). 4. The toner for developing an electrostatic charge image according to 1 to 3, wherein the toner has an average circularity of 0.96 or more.
5. 5. The toner for developing an electrostatic charge image according to 1 to 4, wherein the toner is produced by a wet method.
6). It has at least a toner carrying member, a toner layer thickness regulating member and an electrostatic latent image holding member. The toner layer thickness regulating member thins the toner on the toner carrying member and triboelectrically charges it, and then holds the electrostatic latent image. 6. The electrostatic image developing toner according to any one of 1 to 5 above, which is used in a non-magnetic one-component developing system for developing a toner charged on a body.

According to the present invention, it is possible to provide a toner for developing an electrostatic image that is excellent in chargeability, has good fog, is free from contamination of members, and is suitable for use in a high-speed and long-life machine.
In the toner of the present invention, the ratio A (Dv / Dn) of the volume median diameter Dv to the number median diameter Dn of the toner and the equivalent circle diameter (volume) of the melamine resin particles measured and defined by the method described later. The standard deviation B of the reference) is a specific relationship.

For measurement of the equivalent circle diameter (volume basis) and standard deviation B of the melamine-based resin particles in the present invention, a flow particle analyzer (FPIA 3000: manufactured by Sysmex Corporation) is used. To a dispersion medium obtained by adding 0.25 g of a 20% sodium dodecylbenzenesulfonate aqueous solution (Daiichi Kogyo Seiyaku Co., Ltd., Neogen S20A, hereinafter abbreviated as 20% DBS aqueous solution) to 30 g of demineralized water, 0.005 g of a measurement sample is added. The measurement is performed after ultrasonic treatment for 5 minutes using an ultrasonic cleaner VS-150 manufactured by Vervocrea. The measurement conditions of FPIA3000 are as follows: The dispersoid is dispersed in a dispersion medium (cell sheath: manufactured by Sysmex Corporation) at 5720-7140 / μl, and HPF analysis is performed using a flow type particle analyzer (FPIA3000: manufactured by Sysmex Corporation). The measurement is performed in the HPF mode under the condition of 0.35 μl and HPF detection amount of 2000 to 2500. The equivalent circle diameter (volume basis) and its standard deviation are values automatically calculated in the apparatus by the above measurement.

The equivalent circle diameter (volume basis) of the present invention does not represent the actual primary particle diameter of the melamine resin particles, but the “easy to unravel” of the melamine resin particles when a specific share is applied. Represents. The equivalent circle diameter of the present invention is one of melamine resin particles observed with a scanning electron microscope or the like.
The value is larger than the next particle size. This is because the melamine-based resin particles are measured in the form of aggregates. Therefore, if the value is small, it can be said that the melamine-based resin particles are relatively easy to unravel, and if the value is larger, it is difficult to unravel. be able to. In addition, the standard deviation indicating the variation in the value serves as an index representing the uniformity of the easiness to solve.

The “easy to unravel” and “unevenness of unraveling” of the melamine-based resin particles as described above are considered to correspond to the dispersibility and uniformity when added to the toner. That is, the melamine-based resin particles having a relatively small equivalent circle diameter here are easily unraveled when added to the toner, and are dispersed on the toner surface in a state of being close to primary particles. Such a state is considered to be less liable to be detached than those adhered to the toner surface in the form of aggregates, and the member contamination during printing durability is improved. On the other hand, even if the equivalent circle diameter is small, those having a broad distribution tend to be in a state in which some undissolved particles and unaggregated particles are mixed when added to the toner. This leads to variations in toner chargeability, which is not preferable because the charge amount distribution becomes broad and low-charged toner deteriorates fogging, and remaining aggregates cause member contamination. Therefore, in order to achieve the present invention, in addition to the small equivalent circle diameter, it is important that the distribution is sharp.

In the toner of the present invention, the ratio Dv / Dn (hereinafter referred to as A) of the volume median diameter Dv and the number median diameter Dn of the toner, and the standard deviation (hereinafter referred to as volume basis) of the equivalent circle diameter (volume basis) of the melamine resin particles. , B) must satisfy the following relational expression (1).
B ≦ −41.7A + 53.2 (1)
The present invention has good chargeability and fog when the sharpness of the toner particle distribution represented by A and the standard deviation (B) of the melamine resin particle equivalent circle diameter (volume basis) are in a specific balance. It has been found that there is no contamination of the member, and it is high speed and long life.

  The toner particle distribution represented by A of the present invention has been discussed in the past, and it has been shown that a sharp distribution may have good toner performance. However, in the present invention, the standard deviation of the equivalent circle diameter (volume basis) of the melamine-based resin particles represented by B of the present invention is not so sharp that the distribution represented by A tends to be favorable in the past. In a specific range, the toner performance is found to be good, that is, the balance between A and B is important.

In the present invention, it is more preferable to satisfy the relational expression (2).
B ≦ −41.7A + 52.4 (2)
When the relational expression (1) or (2) is not satisfied, the adhesion of the melamine resin particles to the toner surface is not sufficiently uniform, and the fog and the solid / halftone uniformity tend to be deteriorated. .

  In the present invention, the standard deviation B of the equivalent circle diameter (volume basis) is not particularly limited as long as it is a value satisfying the relational expression of the present invention, but is preferably 9 or less. Among them, 8 is preferable, and 6 or less is particularly preferable. If the standard deviation is too large, the dispersibility when the melamine resin particles are adhered to the toner surface will vary widely, and some of the particles will be dispersed in the state of primary particles or close to them, while remaining as aggregates. Since some remain, the charge amount distribution becomes broad, and the low-charged toner may worsen the fog. In addition, the remaining agglomerates may cause member contamination.

  The melamine resin particles used in the present invention preferably have an equivalent circle diameter (volume basis) of 9 μm or less. Among these, 8 μm or less is preferable, 7 μm or less is more preferable, and 6 μm or less is particularly preferable. Moreover, 0.5 micrometer or more is preferable and 1 micrometer or more is especially preferable. If it is too large, it tends to remain as an aggregate when the melamine resin particles are adhered to the toner surface and tends to cause contamination of the material during printing, and if it is too small, the adhesion to the toner surface becomes too strong. On the contrary, when the toner charge amount is lowered, the fog tends to be deteriorated.

  As the resin used in the melamine resin particles used in the present invention, in addition to so-called melamine / formaldehyde condensation resin, as long as melamine is the main component, melamine / urea / formaldehyde cocondensation resin, melamine / benzoguanamine / formaldehyde cocondensation resin And so on. Among these, in the present invention, a melamine / formaldehyde condensation resin is preferable because a resin having a small equivalent circle diameter (volume basis) or a small standard deviation is easily obtained.

Regarding the melamine resin particles used in the present invention, the reason why the equivalent circle diameter (volume basis) is small or the standard deviation is small is not always clear at the time of external addition, but is presumed as follows. .
When the equivalent circle diameter is small, it is considered that there is a large amount of residual electrolyte on the surface of the melamine resin particles during production, etc., and this generates aggregates due to excessive charging of the melamine resin particles by stirring during external addition Therefore, it is considered that the dispersibility of the toner is improved. Further, the fact that the equivalent circle diameters are uniform is considered that there is a space between the aggregates of the melamine resin particles, and therefore, it is considered that it is easy to unravel at the time of external addition.

  The amount of the melamine resin particles used in the present invention is not particularly limited, but is preferably 0.05 parts by mass or more, and particularly preferably 0.1 parts by mass or more with respect to 100 parts by mass of the toner base particles. Moreover, 0.5 mass part or less is preferable and 0.3 mass part or less is especially preferable. If the amount used is too small, the effect of increasing the charge amount is not sufficient, and fogging and blurring may be a problem. On the other hand, if the amount used is too large, the detached melamine resin particles contaminate the member and cause image defects. There is a case.

  The ratio Dv / Dn (A) of the volume median diameter Dv and the number median diameter Dn of the toner of the present invention is not particularly limited as long as the relational expression of the present invention is satisfied, but is preferably 1.2 or less. 1.17 or less is more preferable, and 1.15 or less is particularly preferable. If Dv / Dn is too large, when melamine resin particles are added to the toner, the positively charged melamine resin particles preferentially adhere to the toner on the small particle size side, which is more strongly negatively charged. Adhesion to the toner on the large particle diameter side having a low static negative chargeability is reduced. As a result, the variation in the charge amount between the toner particles becomes large, the charge amount distribution becomes broad, and the low charge toner tends to deteriorate the fog. In addition, since toner particles with excessive adhesion of melamine-based resin particles are likely to be detached, contamination of members may be deteriorated.

The toner of the present invention preferably has an average circularity of 0.96 or more. Among these, 0.965 or more is more preferable, and 0.97 or more is particularly preferable. Moreover, it is preferable that it is 0.985 or less.
If the average circularity is too small, there will be dents on the surface of the toner particles, and when melamine-based resin particles are added, they will be buried in the dents much, so they will not function effectively as microcarriers, and fog will deteriorate. May be connected. In addition, the melamine-based resin particles fitted in the depressions have weak adhesion strength to the toner particle surfaces, which may cause member contamination due to excessive detachment.
On the other hand, if it is too large, the toner remaining on the photosensitive drum or the transfer belt may not be scraped off well when cleaning with an elastic blade or the like, resulting in an image defect, which may cause a problem of poor cleaning.

  The toner of the present invention can be used in all electrophotographic printers, copiers, etc., regardless of the development method, but when used in a non-magnetic one-component development method that is more strict about chargeability and member contamination, the effect is further improved. Is remarkable and preferable. In addition, as the process speed of the machine increases, the toner charge rise is required to be more rapid. Therefore, the effect of the toner of the present invention is particularly remarkable when used in a machine having a higher process speed. Specifically, 100 mm / sec. Or more, preferably 120 mm / sec. Is more preferable, and 150 mm / sec. The above is particularly preferable.

The melamine-based resin particles used in the present invention can be used for any toner regardless of the production method. However, since the above-described sharp particle size distribution and circularity can be easily controlled, suspension polymerization, emulsion polymerization More preferably, it is used for a toner manufactured by a wet method such as an agglomeration method or a method in which the toner is spheroidized by mechanical impact force or heat treatment.
The method for producing the toner of the present invention is not particularly limited, and includes at least a binder resin and a colorant, and optionally includes a charge control agent, wax, other additives, and the like.

  In the present invention, as the binder resin contained in the toner, resins conventionally used as the binder resin for toner can be appropriately used. For example, as a monomer, a polymerizable monomer having an acidic group (hereinafter sometimes simply referred to as an acidic monomer), a polymerizable monomer having a basic group (hereinafter simply referred to as a basic monomer) A polymerizable monomer having no acidic group or basic group (hereinafter, also referred to as other monomer) may be used. it can.

  When a toner is produced using an emulsion polymerization aggregation method, in the emulsion polymerization step, a polymerizable monomer is usually polymerized in an aqueous medium in the presence of an emulsifier. In supplying the monomer, each monomer may be added separately, or a plurality of types of monomers may be mixed in advance and added simultaneously. The monomer may be added as it is, or may be added as an emulsion mixed and adjusted in advance with water or an emulsifier.

  As the acidic monomer, a polymerizable monomer having a carboxyl group such as acrylic acid, methacrylic acid, maleic acid, fumaric acid, cinnamic acid, a polymerizable monomer having a sulfonic acid group such as sulfonated styrene, Examples thereof include polymerizable monomers having a sulfonamide group such as vinylbenzenesulfonamide. Examples of the basic monomer include aromatic vinyl compounds having an amino group such as aminostyrene, nitrogen-containing heterocyclic-containing polymerizable monomers such as vinylpyridine and vinylpyrrolidone, dimethylaminoethyl acrylate, diethylaminoethyl methacrylate, etc. And (meth) acrylic acid ester having an amino group. These acidic monomers and basic monomers may be used singly or as a mixture of a plurality of types, and may exist as a salt with a counter ion. Among these, it is preferable to use an acidic monomer, more preferably acrylic acid and / or methacrylic acid.

The total amount of the acidic monomer and the basic monomer in 100 parts by mass of the total polymerizable monomers constituting the binder resin is preferably 0.05 parts by mass or more, more preferably 0.5 parts by mass. More preferably, it is 1 part by mass or more, preferably 10 parts by mass or less, more preferably 5 parts by mass or less.
Examples of other polymerizable monomers include styrenes such as styrene, methylstyrene, chlorostyrene, dichlorostyrene, p-tert-butylstyrene, pn-butylstyrene, and pn-nonylstyrene, methyl acrylate, Acrylic esters such as ethyl acrylate, propyl acrylate, n-butyl acrylate, isobutyl acrylate, hydroxyethyl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, n methacrylate -Methacrylic acid esters such as butyl, isobutyl methacrylate, hydroxyethyl methacrylate, 2-ethylhexyl methacrylate, acrylamide, N-propylacrylamide, N, N-dimethylacrylamide, N, N-dipropylacrylic De, N, N-dibutyl acrylamide, and the like, the polymerizable monomer may be used singly, or may be used in combination.

  Furthermore, when the binder resin is a cross-linked resin, a polyfunctional monomer having radical polymerizability is used together with the above polymerizable monomer, for example, divinylbenzene, hexanediol diacrylate, ethylene glycol dimethacrylate, Examples include diethylene glycol dimethacrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, neopentyl glycol dimethacrylate, neopentyl glycol diacrylate, and diallyl phthalate. It is also possible to use a polymerizable monomer having a reactive group in a pendant group, such as glycidyl methacrylate, methylol acrylamide, acrolein and the like. Among these, radically polymerizable bifunctional polymerizable monomers are preferable, and divinylbenzene and hexanediol diacrylate are particularly preferable. These polyfunctional polymerizable monomers may be used alone or as a mixture of plural kinds.

When the binder resin is polymerized by emulsion polymerization, a known surfactant can be used as an emulsifier. As the surfactant, one or more surfactants selected from cationic surfactants, anionic surfactants, and nonionic surfactants can be used in combination.
Examples of the cationic surfactant include dodecyl ammonium chloride, dodecyl ammonium bromide, dodecyl trimethyl ammonium bromide, dodecyl pyridinium chloride, dodecyl pyridinium bromide, hexadecyl trimethyl ammonium bromide, and examples of the anionic surfactant include And fatty acid soap such as sodium stearate and sodium dodecanoate, sodium dodecyl sulfate, sodium dodecylbenzenesulfonate, sodium lauryl sulfate and the like. Nonionic surfactants include, for example, polyoxyethylene dodecyl ether, polyoxyethylene hexadecyl ether, polyoxyethylene nonyl phenyl ether, polyoxyethylene lauryl ether, polyoxyethylene sorbitan monooleate ether, monodecanoyl sucrose, etc. Is mentioned.

The amount of the emulsifier used in the present invention is preferably 0.1 parts by mass or more and 10 parts by mass or less with respect to 100 parts by mass of the polymerizable monomer. In addition, these emulsifiers can be used as protective colloids, for example, one or more of partially or completely saponified polyvinyl alcohols such as polyvinyl alcohol and cellulose derivatives such as hydroxyethyl cellulose.
The volume average particle diameter of the polymer primary particles obtained by emulsion polymerization is usually 0.02 μm or more, preferably 0.05 μm or more, more preferably 0.1 μm or more, and usually 3 μm or less, preferably 2 μm or less, more preferably. Is desirably 1 μm or less. When the particle size is smaller than the above range, it may be difficult to control the aggregation rate in the aggregation process. When the particle size is larger than the above range, the particle size of the toner particles obtained by aggregation tends to be large, It may be difficult to obtain a toner having a particle size of

In this invention, a well-known polymerization initiator can be used as needed, A polymerization initiator can be used 1 type or in combination of 2 or more types. For example, persulfates such as potassium persulfate, sodium persulfate, ammonium persulfate, and the like, and redox initiators combining these persulfates as a component with a reducing agent such as acidic sodium sulfite, hydrogen peroxide, 4,4 '−
Redox initiation in which water-soluble polymerization initiators such as azobiscyanovaleric acid, t-butyl hydroperoxide, cumene hydroperoxide, etc., and these water-soluble polymerizable initiators are combined with a reducing agent such as ferrous salt as one component Agent systems, benzoyl peroxide, 2,2′-azobis-isobutyronitrile, and the like are used. These polymerization initiators may be added to the polymerization system before, simultaneously with the addition of the monomer, or after the addition, and these addition methods may be combined as necessary.

In the present invention, a known chain transfer agent can be used as necessary, and specific examples include t-dodecyl mercaptan, 2-mercaptoethanol, diisopropyl xanthogen, carbon tetrachloride, trichlorobromomethane and the like. It is done. The chain transfer agent may be used alone or in combination of two or more, and is used in an amount of 0 to 5% by weight based on the polymerizable monomer.
Moreover, in this invention, a well-known suspension stabilizer can be used as needed. Specific examples of the suspension stabilizer include calcium phosphate, magnesium phosphate calcium hydroxide, magnesium hydroxide and the like. These may be used alone or in combination of two or more, and may be used in an amount of 1 part by mass or more and 10 parts by mass or less with respect to 100 parts by mass of the polymerizable monomer.

Both the polymerization initiator and the suspension stabilizer may be added to the polymerization system at any time before, simultaneously with, or after the addition of the polymerizable monomer. You may combine.
In addition, a pH adjuster, a polymerization degree adjuster, an antifoaming agent, and the like can be appropriately added to the reaction system.

The toner obtained by the production method and apparatus of the present invention preferably contains a wax in order to impart releasability. Any wax can be used as long as it has releasability.
Specifically, for example, olefin waxes such as low molecular weight polyethylene, low molecular weight polypropylene and copolymer polyethylene; paraffin wax; ester waxes having a long-chain aliphatic group such as behenyl behenate, montanate ester, stearyl stearate A vegetable wax such as hydrogenated castor oil carnauba wax; a ketone having a long chain alkyl group such as distearyl ketone; a silicone having an alkyl group; a higher fatty acid such as stearic acid; a long chain aliphatic alcohol such as eicosanol; Examples include carboxylic acid esters or partial esters of polyhydric alcohols obtained from polyhydric alcohols such as erythritol and long chain fatty acids; higher fatty acid amides such as oleic acid amides and stearic acid amides; low molecular weight polyesters.

  Among these waxes, in order to improve fixability, the melting point of the wax is preferably 30 ° C. or higher, more preferably 40 ° C. or higher, and particularly preferably 50 ° C. or higher. Moreover, 100 degrees C or less is preferable, 90 degrees C or less is more preferable, and 80 degrees C or less is especially preferable. If the melting point is too low, the wax may be exposed on the surface after fixing, and stickiness may occur. On the other hand, if the melting point is too high, the fixability at low temperatures may be poor.

  As the wax compound species, higher fatty acid ester waxes are preferable. Specific examples of the higher fatty acid ester wax include, for example, behenyl behenate, stearyl stearate, stearate ester of pentaerythritol, glyceride montanate, and the like, and fatty acids having 15 to 30 carbon atoms and 1 to 5 valent alcohols. The esters are preferred. Moreover, as an alcohol component which comprises ester, a C10-30 thing is preferable in the case of monohydric alcohol, and a C3-C10 thing is preferable in the case of a polyhydric alcohol.

The above waxes may be used alone or in combination. Further, the melting point of the wax compound can be appropriately selected depending on the fixing temperature for fixing the toner.
In the present invention, the amount of the wax is preferably 1 part by mass or more per 100 parts by mass of the toner, more preferably 2 parts by mass or more, and further preferably 5 parts by mass or more. Moreover, it is preferable that it is 40 mass parts or less, More preferably, it is 35 mass parts or less, More preferably, it is 30 mass parts or less. When the wax content in the toner is less than the above range, the performance such as high temperature offset property may not be sufficient, and when it exceeds the above range, the blocking resistance is insufficient or the wax leaks from the toner. May contaminate the device.

  A known colorant can be arbitrarily used as the colorant of the present invention. Specific examples of the colorant include carbon black, aniline blue, phthalocyanine blue, phthalocyanine green, Hansa yellow, rhodamine dyes, chrome yellow, quinacridone, benzidine yellow, rose bengal, triallylmethane dye, monoazo, Any known dyes and pigments such as disazo dyes and condensed azo dyes can be used alone or in combination. In the case of a full color toner, it is preferable to use benzidine yellow for yellow, monoazo and condensed azo dyes, magenta for quinacridone and monoazo dyes, and cyan for phthalocyanine blue. The colorant is preferably used so as to be 3 parts by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the polymer primary particles.

  The blending of the colorant in the emulsion polymerization aggregation method is usually performed in an aggregation step. A dispersion of polymer primary particles and a dispersion of colorant particles are mixed to form a mixed dispersion, which is then aggregated to form a particle aggregate. The colorant is preferably used in a state of being dispersed in water in the presence of an emulsifier, and the volume average particle diameter of the colorant particles is 0.01 or more, more preferably 0.05 μm or more, and more preferably 3 μm or less. 1 μm.

  In the present invention, when a charge control agent is used, any known one can be used alone or in combination. For example, a quaternary ammonium salt, a basic or electron donating metal as a positive charge control agent. Substances such as metal chelates, metal salts of organic acids, metal-containing dyes, nigrosine dyes, amide group-containing compounds, phenolic compounds, naphthol compounds and their metal salts, urethane bond-containing compounds, Examples include acidic or electron-withdrawing organic substances.

  In addition, when the toner for developing an electrostatic image obtained by the production method of the present invention is used as a toner other than a black toner in a color toner or a full color toner, a charge control agent that is colorless or light in color and does not impair the color tone of the toner is used. It is preferable to use, for example, a quaternary ammonium salt compound as a positively chargeable charge control agent, a metal salt of salicylic acid or an alkylsalicylic acid with chromium, zinc, aluminum, a metal complex as a negatively chargeable charge control agent, Hydroxys such as metal salts of benzylic acid, metal complexes, amide compounds, phenolic compounds, naphthol compounds, phenolamide compounds, 4,4′-methylenebis [2- [N- (4-chlorophenyl) amide] -3-hydroxynaphthalene] Naphthalene compounds are preferred.

  In the present invention, when a charge control agent is contained in the toner using the emulsion polymerization aggregation method, the charge control agent is added together with a polymerizable monomer or the like at the time of emulsion polymerization, or together with the polymer primary particles and the colorant. It can be blended by a method such as adding in the agglomeration step, or adding after the polymer primary particles and the colorant are aggregated to almost the target particle size. Among these, it is preferable to disperse the charge control agent in water using a surfactant and add it to the aggregation step as a dispersion having a volume average particle size of 0.01 μm or more and 3 μm or less.

The toner of the present invention may be produced by any polymerization method such as a suspension polymerization method, an emulsion polymerization aggregation method, or a dissolution suspension method, and is not particularly limited.
In the present invention, as a method for producing a suspension polymerization toner, a coloring agent, a polymerization initiator, and, if necessary, a wax, a polar resin, a charge control agent, a crosslinking agent, etc. in the above-mentioned binder resin monomer. An additive is added to prepare a monomer composition that is uniformly dissolved or dispersed. This monomer composition is dispersed in an aqueous medium containing a dispersion stabilizer and the like. Preferably, granulation is performed by adjusting the stirring speed and time so that the droplets of the monomer composition have a desired toner particle size. Thereafter, polymerization is performed by stirring to such an extent that the particle state is maintained and the sedimentation of the particles is prevented by the action of the dispersion stabilizer. These are collected by washing and filtration, and dried to obtain toner mother particles.

  As a production method of the emulsion polymerization aggregation method, polymer primary particles of a binder resin monomer obtained by emulsion polymerization, a colorant dispersion, a wax dispersion, etc. are prepared, and these are dispersed in an aqueous medium. By carrying out heating or the like, it undergoes an agglomeration step and an aging step. These are collected by washing and filtration, and dried to obtain toner mother particles. Further, if necessary, toner can be obtained by external addition or the like.

  In the emulsion polymerization aggregation method, the aggregation is usually carried out in a tank equipped with a stirrer, but there are a heating method, a method of adding an electrolyte, and a method of combining them. When polymer primary particles are agglomerated with stirring to obtain particle aggregates of the desired size, the particle size of the particle aggregates is controlled based on the balance between the agglomeration force between the particles and the shearing force due to agitation. However, the cohesive force can be increased by heating or adding an electrolyte.

In the present invention, the electrolyte in the case of performing aggregation by adding an electrolyte may be either an organic salt or an inorganic salt. Specifically, NaCl, KCl, LiCl, Na ₂ SO ₄ , K ₂ SO ₄ , Li ₂ SO ₄ , MgCl ₂ , CaCl ₂ , MgSO ₄ , CaSO ₄ , ZnSO ₄ , Al ₂ (SO ₄ ) ₃ , Fe ₂ (SO ₄ ) ₃ , CH ₃ COONa, C ₆ H ₅ SO ₃ Na, etc. It is done. Of these, inorganic salts having a divalent or higher polyvalent metal cation are preferred.

  In the present invention, the amount of electrolyte added varies depending on the type of electrolyte, target particle size, etc., but is preferably 0.05 parts by mass or more, and 0.1 parts by mass with respect to 100 parts by mass of the solid component of the mixed dispersion. Part or more is more preferable. Further, it is preferably 25 parts by mass or less, more preferably 15 parts by mass or less, and particularly preferably 10 parts by mass or less. When the amount added is less than the above range, the agglomeration reaction progresses slowly and fine powders of 1 μm or less remain after the agglomeration reaction, and the average particle size of the obtained particle aggregate does not reach the target particle size. If the amount is larger than the above range, it is likely to be agglomerated rapidly, making it difficult to control the particle size, and the resulting agglomerated particles may contain problems such as coarse powder or irregular shapes. There is. When the aggregation is performed by adding an electrolyte, the aggregation temperature is 20 ° C. or higher, more preferably 30 ° C. or higher, and 70 ° C. or lower, more preferably 60 ° C. or lower.

The aggregation temperature in the case of performing aggregation only by heating without using an electrolyte is preferably (Tg-20) ° C. or higher, and more preferably (Tg-10) ° C. or higher, where Tg is the glass transition temperature of the polymer primary particles. . Moreover, Tg or less is preferable and (Tg-5) degree C or less is preferable.
The time required for agglomeration is optimized depending on the shape of the apparatus and the processing scale, but in order for the toner particle size to reach the target particle size, it is usually held at the predetermined temperature for at least 30 minutes. desirable. The temperature rise until reaching the predetermined temperature may be raised at a constant rate, or may be raised stepwise.

If necessary, particles having adhered or fixed resin particles may be formed on the surface of the particle aggregate after the above-described aggregation treatment. In some cases, the chargeability and heat resistance of the obtained toner can be improved by attaching or fixing the resin particles whose properties are controlled to the surface of the particle aggregate, and the effect of the present invention can be further enhanced. .
When resin particles having a glass transition temperature higher than that of the polymer primary particles are used as the resin particles, it is preferable because blocking resistance can be further improved without impairing fixing properties. The volume average particle size of the resin particles is preferably 0.02 μm or more, and more preferably 0.05 μm or more. Moreover, 3 micrometers or less, Furthermore, 1.5 micrometers or less are preferable. As the resin particles, those obtained by emulsion polymerization of monomers similar to the polymerizable monomers used for the above-mentioned polymer primary particles can be used.

Resin particles are usually used as a dispersion dispersed in water or a liquid mainly composed of water with a surfactant. However, when a charge control agent is added after the aggregation treatment, charge control is performed on the dispersion containing particle aggregates. It is preferable to add the resin particles after adding the agent.
In order to increase the stability of the particle aggregate obtained in the aggregation step, it is preferable to perform fusion in the aggregated particles in the aging step after the aggregation step. The temperature of the ripening step is preferably not less than Tg of the polymer primary particles, more preferably not less than 5 ° C higher than Tg, and preferably not more than 80 ° C higher than Tg, more preferably not less than 50 ° C higher than Tg. It is as follows. The time required for the aging step varies depending on the shape of the target toner, but after reaching the glass transition temperature or higher of the polymer primary particles, it is usually held for 0.1 to 10 hours, preferably 1 to 6 hours. Is desirable.

  In addition, it is preferable to add a surfactant or raise the pH value after the aggregation process, preferably before the aging process or during the aging process. As the surfactant used here, one or more emulsifiers can be selected from the emulsifiers that can be used when producing the polymer primary particles. In particular, the emulsifiers used when producing the polymer primary particles. It is preferable to use the same. Although the addition amount in the case of adding surfactant is not limited, Preferably it is 0.1 mass part or more with respect to 100 mass parts of solid components of a mixed dispersion, More preferably, it is 1 mass part or more, More preferably, it is 3 masses It is preferably 20 parts by mass or less, more preferably 15 parts by mass or less, and still more preferably 10 parts by mass or less. After the aggregation process, before the completion of the ripening process, by adding a surfactant or raising the pH value, it is possible to suppress aggregation of the particle aggregates aggregated in the aggregation process, In some cases, the generation of coarse particles can be suppressed.

By heat treatment in the aging step, the polymer primary particles in the aggregate are fused and integrated, and the toner particle shape as the aggregate becomes close to a spherical shape. The particle aggregate before the aging step is considered to be an aggregate due to electrostatic or physical aggregation of the polymer primary particles, but after the aging step, the polymer primary particles constituting the particle aggregate are fused to each other. In addition, the shape of the toner particles can be made nearly spherical. According to such an aging process, by controlling the temperature and time of the aging process, the shape of the polymer primary particles is agglomerated, a potato type with advanced fusion, a spherical form with further fusion For example, various shapes of toner can be manufactured according to the purpose.
The obtained particles are subjected to solid-liquid separation by a known method, the particles are collected, and washed and dried as necessary to obtain target toner mother particles.

<External addition process>
The toner of the present invention can be obtained by adhering or fixing at least melamine resin particles on the surface of the toner base particles. However, it is known as an external additive as long as the effects of the present invention are not impaired. The toner particles may be used in combination with or adhered to the surface of the toner base particles.

Examples of the “other particles” include inorganic particles such as silica, aluminum oxide (alumina), zinc oxide, tin oxide, barium titanate and strontium titanate; organic acid salt particles such as zinc stearate and calcium stearate; Examples thereof include organic resin particles such as acid ester polymer particles, acrylic acid ester polymer particles, styrene-methacrylic acid ester copolymer particles, and styrene-acrylic acid ester copolymer particles.

  The blending ratio between the melamine resin particles of the present invention and “other particles” is not particularly limited, and the amount of all external additives composed of the melamine resin particles and “other particles” is not particularly limited. The amount of all external additives used is preferably 1 part by mass or more, more preferably 1.5 parts by mass or more, and particularly preferably 2 parts by mass or more with respect to 100 parts by mass of the base particles. Moreover, 5 mass parts or less are preferable, and 4 mass parts or less are more preferable. If the amount used is too small, the fluidity may be deteriorated or the charge amount may not be controlled. On the other hand, if the amount used is too large, the free additive that has not adhered can contaminate the components in the cartridge. However, this may cause image defects.

The order in which the melamine resin particles used in the present invention are adhered or fixed to the surface of the toner base particles is not particularly limited, but from the viewpoint of the working mechanism of the present invention, It is preferable to add later.
In the present invention, the method for adhering or fixing the melamine-based resin particles and “other particles” to the surface of the toner base particles is not particularly limited, and a mixer generally used for toner production can be used. Specifically, it is performed by uniformly stirring and mixing with a mixer such as a Henschel mixer, a V-type blender, a Redige mixer, or a Q-mixer.

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to the following examples unless it exceeds the gist. In the following examples, “part” means “part by mass”.
<Measurement method of average particle diameter of polymer primary particles>
Nikkiso Co., Ltd., Model: Microtrac Nanotrac 150 (hereinafter abbreviated as “Nanotrack”), according to the instruction manual of NanoTrack, using its analysis software Microtrac Particle Analyzer Ver10.1.2.-019EE Using ion-exchanged water having a degree of 0.5 μS / cm as a dispersion medium, the measurement was performed by the method described in the instruction manual under the following conditions or by inputting the following conditions.
Solvent refractive index: 1.333
・ Measurement time: 100 seconds
・ Number of measurements: 1 time
-Particle refractive index: 1.59
・ Transparency: Transmission
・ Shape: Spherical shape
Density: 1.04

<Method for Measuring Volume Median Diameter (Dv) and Number Median Diameter (Dn) of Toner Particles>
Use Beckman Coulter's Multisizer III (aperture diameter 100 μm) (hereinafter abbreviated as “Multisizer”), use the company's Isoton II as the dispersion medium, and disperse so that the dispersoid concentration is 0.03% by mass. And measured. The measurement particle diameter range is from 2.00 to 64.00 μm, and this range is discretized into 256 divisions so as to be equidistant on a logarithmic scale, and the volume calculated based on the statistical values on the basis of the volume is the volume. The median diameter (Dv) and the number median diameter (Dn) were calculated based on the statistical values based on the number.

<Measuring method of average circularity of toner particles>
The average circularity is determined by dispersing the dispersoid in a dispersion medium (Cell Sheath: Sysmex) at 5720-7140 / μl, and using a flow particle analyzer (FPIA 3000: Sysmex) to analyze the amount of HPF. It measured by HPF mode on 0.35 microliters and HPF detection amount 2000-2500 conditions. The average circularity value is automatically calculated and displayed in the apparatus by the above measurement.

<Manufacture of melamine resin particles>
Melamine and formaldehyde (37% formalin aqueous solution) were added with an alkaline catalyst in a reaction kettle and reacted by heating while adjusting the pH, and then dried for one day using a freeze dryer to obtain melamine resin particles. The melamine resin particles A to G having different particle sizes and particle size distributions were obtained by adjusting the charging amount, temperature, and reaction time during the reaction. Table 1 shows the equivalent circle diameter (volume basis) and the standard deviation thereof according to the aforementioned method.

<Manufacture of mother particle A>
<Preparation of wax / long-chain polymerizable monomer dispersion A1>
27 parts of paraffin wax (HNP-9 manufactured by Nippon Seiki Co., Ltd.), 2.8 parts of stearyl acrylate (manufactured by Tokyo Chemical Industry Co., Ltd.), 1.9 parts of 20% DBS aqueous solution and 68.3 parts of demineralized water were heated to 90 ° C. The mixture was stirred for 10 minutes using a homomixer (Mark II f model, manufactured by Koki Kogyo Co., Ltd.). Next, this dispersion was heated to 90 ° C., and circulation emulsification was started under a pressure condition of 25 MPa using a homogenizer (manufactured by Gorin, 15-M-8PA type). A wax / long-chain polymerizable monomer dispersion A1 (emulsion solid content concentration = 30.2%) was prepared by dispersing until the diameter (MV) reached 250 nm.

<Preparation of silicone wax dispersion A2>
27 parts of alkyl-modified silicone wax), 1.9 parts of 20% DBS aqueous solution, and 71.1 parts of demineralized water are placed in a stainless steel container and heated to 90 ° C. Stir for minutes. Next, this dispersion was heated to 99 ° C., and circulation emulsification was started under a pressure of 45 MPa using a homogenizer (manufactured by Gorin Co., Ltd., 15-M-8PA type). MV) was dispersed to 240 nm to prepare a silicone wax dispersion A2 (emulsion solid content concentration = 27.4%).

<Preparation of polymer primary particle dispersion A1>
35.6 parts by weight of wax / long-chain polymerizable monomer dispersion A1 and 259 demineralized water in a reactor equipped with a stirring device (three blades), a heating / cooling device, a concentrating device, and a raw material / auxiliary charging device The temperature was raised to 90 ° C. under a nitrogen stream while stirring and stirring.
Thereafter, the following mixture of monomers and an aqueous emulsifier solution was added over 5 hours from the start of polymerization while stirring was continued. The time when the mixture of the monomers and the emulsifier aqueous solution was started to be dropped was set as the polymerization start, and the following initiator aqueous solution was added over 4.5 hours from 30 minutes after the start of the polymerization. The aqueous solution of the agent was added over 2 hours, and the internal temperature was maintained at 90 ° C. for 1 hour while continuing stirring.
[Monomers]
Styrene 76.8 parts Butyl acrylate 23.2 parts Acrylic acid 1.5 parts Tetrachlorobromomethane 1.0 part Hexanediol diacrylate 0.7 parts
[Emulsifier aqueous solution]
20% DBS aqueous solution 1.0 part demineralized water 67.1 parts
[Initiator aqueous solution]
8% aqueous hydrogen peroxide solution 15.5 parts 8% L (+)-ascorbic acid aqueous solution 15.5 parts
[Additional initiator aqueous solution]
8% L (+)-ascorbic acid aqueous solution 14.2 parts After the completion of the polymerization reaction, the mixture was cooled to obtain a milky white primary polymer particle dispersion A1. The volume average particle diameter (MV) measured using a nanotrack was 280 nm, and the solid content concentration was 21.1 wt%.

<Preparation of polymer primary particle dispersion A2>
In a reactor equipped with a stirring device (three blades), a heating / cooling device, a concentrating device, and a raw material / auxiliary charging device, 23.6 parts by weight of silicone wax dispersion A2, 1.5 parts by weight of 20% DBS aqueous solution, 324 parts of demineralized water was added, the temperature was raised to 90 ° C. under a nitrogen stream, and 3.2 parts of an 8% aqueous hydrogen peroxide solution and 3.2 parts of an 8% L (+)-ascorbic acid aqueous solution were added all at once with stirring. .
5 minutes later, polymerization of the following mixture of monomers and emulsifier aqueous solution was started (from the time when 3.2 parts of 8% hydrogen peroxide aqueous solution and 3.2 parts of 8% L (+)-ascorbic acid aqueous solution were added all at once. After 5 minutes), the following initiator aqueous solution was added over 6 hours from the start of polymerization, and the internal temperature was maintained at 90 ° C. for 1 hour with further stirring.

[Monomers]
Styrene 92.5 parts Butyl acrylate 7.5 parts Acrylic acid 1.5 parts Tetrachlorobromomethane 0.6 parts
[Emulsifier aqueous solution]
20% DBS aqueous solution 1.5 parts demineralized water 66.2 parts
[Initiator aqueous solution]
8% aqueous hydrogen peroxide solution 18.9 parts 8% L (+)-ascorbic acid aqueous solution 18.9 parts After completion of the polymerization reaction, the mixture was cooled to obtain a milky white primary polymer particle dispersion A2. The volume average particle diameter (MV) measured using a nanotrack was 290 nm, and the solid content concentration was 19.0% by weight.

<Preparation of Colorant Dispersion A>
In a container equipped with a stirrer (propeller blade), carbon black (Mitsubishi Chemical Corporation, Mitsubishi Carbon Black MA100S) 20 parts, 20% DBS aqueous solution 1 part, nonionic surfactant (Kao Corporation, Emulgen 120) 4 parts, 75 parts of ion-exchanged water having an electric conductivity of 2 μS / cm was added and predispersed to obtain a premix solution. The volume average diameter (Mv) of carbon black in the premix solution was 90 μm.

The premix solution was supplied to a wet bead mill and subjected to one-pass dispersion. The inner diameter of the stator was φ75 mm, the separator diameter was φ60 mm, the distance between the separator and the disk was 15 mm, and zirconia beads having a diameter of 100 μm (true density of 6.0 g / cm ³ ) were used as a dispersion medium.
The black colorant dispersion A is obtained by continuously supplying the premix slurry from a supply port at a supply speed of 50 L / hr by a non-pulsating metering pump and continuously discharging from the discharge port while keeping the rotation speed of the rotor constant. Got. The volume average diameter (Mv) of the colorant in the colorant dispersion was 150 nm.

<Manufacture of mother particle A>
Polymer primary particle dispersion A1 95 parts as solid content Polymer primary particle dispersion A2 5 parts as solid content
Colorant particle dispersion A 6 parts as colorant solids
20% DBS aqueous solution 0.1 parts as a solid content Using the above components, mother particles were produced by the following procedure.

Polymer primary particle dispersion A1 and 20% DBS aqueous solution were charged to a mixer equipped with a stirrer (double helical blade), heating / cooling device, concentrating device, and raw material / auxiliary charging device, and the internal temperature was 5 ° C. at 5 ° C. Mix evenly for minutes. Subsequently, while stirring at an internal temperature of 12 ° C., 0.52 parts of FeSO4 · 7H2O as a 5% aqueous solution of ferrous sulfate is added over 5 minutes, and then the colorant particle dispersion A is added over 5 minutes. The mixture was uniformly mixed at an internal temperature of 12 ° C., and a 0.5% aqueous solution of aluminum sulfate was added dropwise under the same conditions (the solid content with respect to the resin solid content was 0.10 parts). Thereafter, the temperature was raised to 53 ° C. over 75 minutes, and further raised to 56 ° C. over 90 minutes. Here, when the volume median diameter was measured using a multisizer, it was 5.2 μm. Thereafter, the polymer primary particle dispersion A2 was added over 3 minutes and held for 60 minutes, followed by addition of 20% DBS aqueous solution (6 parts as solids) over 10 minutes and then over 90 minutes over 90 minutes. The temperature was raised to 0 ° C. and held for 75 minutes.

  Thereafter, the slurry obtained by cooling to 30 ° C. over 20 minutes was extracted, and suction filtration was performed with an aspirator using 5 types C (No5C manufactured by Toyo Roshi Kaisha, Ltd.) filter paper. The cake remaining on the filter paper is transferred to a stainless steel container having an internal volume of 10 L equipped with a stirrer (propeller blade), added with 8 kg of ion-exchanged water having an electric conductivity of 1 μS / cm, and uniformly dispersed by stirring at 50 rpm. Stirred for 30 minutes.

  Then, suction filtration is performed with an aspirator again using filter paper of 5 types C (Toyo Filter Paper Co., Ltd. No5C), and the solid matter remaining on the filter paper is again equipped with a stirrer (propeller blade) and has an electric conductivity of 1 μS / cm. It was transferred to a 10 L container with 8 kg of ion-exchanged water, and evenly dispersed by stirring at 50 rpm and kept stirring for 30 minutes. When this process was repeated 5 times, the electrical conductivity of the filtrate was 2 μS / cm.

The cake obtained here was spread on a stainless pad so as to have a height of 20 mm, and dried in a blow dryer set at 40 ° C. for 48 hours to obtain mother particles A.
Further, by adjusting the holding time at 53 ° C. and the holding time at 90 ° C., mother particles B to J having different particle size distribution and circularity were obtained. Table 2 shows the particle size distribution and the average circularity.

<Example 1>
<Manufacture of toner A>
Into a Henschel mixer manufactured by Mitsui Mining Co., Ltd., mother particle A (100 parts) is charged, followed by 2.0 parts of hydrophobic silica H05TD (manufactured by Clariant Japan), hydrophobic silica H30TD (manufactured by Clariant Japan) 0 Toner A was obtained by adding 0.2 part of melamine resin particles A and stirring and mixing and sieving. Toner A had a volume median diameter Dv of 5.58 μm, a number median diameter Dn of 5.20 μm, and a toner particle size distribution Dv / Dn of 1.073. The average circularity of toner A was 0.974.

<Example 2>
<Manufacture of toner B>
In Example 1, toner B was obtained in the same manner as in Example 1 except that 100 parts of mother particle B was used instead of mother particle A and 0.2 part of melamine resin particle B was used instead of melamine resin particle A. . Toner B had a volume median diameter Dv of 5.74 μm, a number median diameter Dn of 5.27 μm, and a toner particle size distribution Dv / Dn of 1.089. The average circularity of toner B was 0.973.

<Example 3>
<Manufacture of toner C>
In Example 1, Toner C was obtained in the same manner as in Example 1 except that 100 parts of mother particles C were used instead of mother particles A and 0.2 parts of melamine resin particles C were used instead of melamine resin particles A. . Toner C had a volume median diameter Dv of 5.91 μm, a number median diameter Dn of 5.37 μm, and a toner particle size distribution Dv / Dn of 1.101. The average circularity of the toner C was 0.974.

<Example 4>
<Manufacture of toner D>
In Example 1, toner D was obtained in the same manner as in Example 1 except that 100 parts of mother particles D were used instead of mother particles A and 0.2 parts of melamine resin particles C were used instead of melamine resin particles A. . Toner D had a volume median diameter Dv of 5.47 μm, a number median diameter Dn of 4.83 μm, and a toner particle size distribution Dv / Dn of 1.133. The average circularity of the toner D was 0.973.

<Example 5>
<Manufacture of toner E>
In Example 1, Toner E was obtained in the same manner as Example 1 except that 100 parts of mother particles E were used instead of mother particles A and 0.2 parts of melamine resin particles D were used instead of melamine resin particles A. . Toner E had a volume median diameter Dv of 5.66 μm, a number median diameter Dn of 4.92 μm, and a toner particle size distribution Dv / Dn of 1.150. The average circularity of the toner E was 0.972.

<Example 6>
<Manufacture of toner F>
In Example 1, toner F was obtained in the same manner as in Example 1 except that 100 parts of mother particles F were used instead of mother particles A and 0.2 parts of melamine resin particles E were used instead of melamine resin particles A. . Toner F had a volume median diameter Dv of 5.71 μm, a number median diameter Dn of 5.10 μm, and a toner particle size distribution Dv / Dn of 1.120. The average circularity of the toner F was 0.973.

<Example 7>
<Manufacture of toner G>
In Example 1, Toner G was obtained in the same manner as Example 1 except that 100 parts of mother particles G were used instead of mother particles A and 0.2 parts of melamine resin particles F were used instead of melamine resin particles A. . Toner G had a volume median diameter Dv of 5.61 μm, a number median diameter Dn of 5.17 μm, and a toner particle size distribution Dv / Dn of 1.085. The average circularity of the toner G was 0.969.

<Example 8>
<Manufacture of toner H>
In Example 1, toner H was obtained in the same manner as in Example 1 except that 100 parts of mother particles H were used instead of mother particles A and 0.2 parts of melamine resin particles G were used instead of melamine resin particles A. . Toner H had a volume median diameter Dv of 5.79 μm, a number median diameter Dn of 5.05 μm and a toner particle size distribution Dv / Dn of 1.147. The average circularity of the toner H was 0.973.

<Comparative Example 1>
<Manufacture of Toner I>
In Example 1, Toner I was obtained in the same manner as in Example 1 except that 100 parts of base particle I was used instead of base particle A. Toner I had a volume median diameter Dv of 5.70 μm, a number median diameter Dn of 5.16 μm, and a toner particle size distribution Dv / Dn of 1.105. The average circularity of the toner I was 0.973.

<Comparative example 2>
<Manufacture of toner J>
In Example 1, Toner J was obtained in the same manner as in Example 1 except that 100 parts of mother particles J were used instead of mother particles A and 0.2 parts of melamine resin particles C were used instead of melamine resin particles A. . Toner J had a volume median diameter Dv of 5.63 μm, a number median diameter Dn of 4.91 μm, and a toner particle size distribution Dv / Dn of 1.147. The average circularity of the toner J was 0.971.

<Live-action method>
The resulting toner is a non-magnetic one component (using an organic photoreceptor), roller (PCR) charging, rubber development roller contact development system, development speed 164 mm / second, tandem system, belt transport system, direct transfer system, blade drum Using a cleaning method, a photograph was taken with a 600 dpi full color printer having a guaranteed life of 30,000 sheets at a 5% printing rate.

After printing a 1% printing rate chart up to 10,000 sheets intermittently in an environment of 25 ° C. and 50%, the printer was left in an environment of 28 ° C. and 80% for one day. Thereafter, printing was performed as follows, and the degree of contamination of the fog and the developing tank member (PCR contamination) was evaluated.

<Evaluation method of fog>
At the time of printing, the toner adhering to the white background portion of the photosensitive drum before the transfer process to paper was copied with a mending tape (manufactured by Sumitomo 3M Limited) and pasted on 80 g / m ² of printing paper. . Further, after a mending tape was directly applied to the same sheet for comparison, the color difference ΔE between the two was measured with a spectrocolorimetric densitometer X-Rite 939 (manufactured by X-Rite) to evaluate fog. Judgment criteria were as follows.
Δ: ΔE is less than 4 ○: ΔE is 4 or more and less than 6 Δ: ΔE is 6 or more and less than 10 ×: ΔE is 10 or more <PCR contamination evaluation method>
After completion of printing, the PCR was visually observed to evaluate the degree of contamination. Judgment criteria were as follows.
A: Very good with no contamination.
○: Almost no contamination and good.
Δ: Slightly contaminated and may develop into image defects.
X: Severe contamination is observed and image defects are generated.
The results are shown in Table 3.

Claims (6)

A negatively chargeable toner comprising at least a binder resin and a colorant and having at least melamine resin particles adhered or fixed to a surface thereof, wherein the ratio of the volume median diameter Dv to the number median diameter Dn is Dv / An electrostatic charge image developing toner, wherein Dn is A and the standard deviation of the equivalent circle diameter (volume basis) of the melamine resin particles is B, which satisfies the following relational expression (1).
B ≦ −41.7A + 53.2 (1) 2. The electrostatic image developing toner according to claim 1, wherein A and B satisfy the following relational expression (2).
B ≦ −41.7A + 52.4 (2)   The toner for developing an electrostatic charge image according to claim 1, wherein the equivalent circle diameter (volume basis) of the melamine resin particles is 9 μm or less.   4. The electrostatic image developing toner according to claim 1, wherein the toner has an average circularity of 0.96 or more.   The electrostatic image developing toner according to claim 1, wherein the toner is produced by a wet method.   It has at least a toner carrying member, a toner layer thickness regulating member and an electrostatic latent image holding member. The toner layer thickness regulating member thins the toner on the toner carrying member and triboelectrically charges it, and then holds the electrostatic latent image. 6. The electrostatic image developing toner according to claim 1, wherein the toner is used in a non-magnetic one-component developing system in which a toner charged on a body is developed.